Process for treatment of hydrogel lens with thiols

Abstract

The invention provides a method of treating hydrogels formed from the polymerization of monomers having reactive olefinic double bonds by contacting them with reactive thiol compounds. In a preferred embodiment where the hydrogel structure includes a cis-glycol containing unit, a suitable thiol is used in conjunction with a borate buffer. The present invention also provides materials that are treated with the above thiol compounds.

We claim: 
     
       1. A method for reducing the irritant effect resulting when a hydrogel polymer in the shape of a contact lens and formed by the copolymerization of a major amount of a monoester of an olefinic acid selected from the group of acrylic and methacrylic acids having a single olefinic double bond and a polyhydric lower alcohol, and a minor amount of a polymerizable diester of one of said acids, wherein said diester contains at least two olefinic double bonds, is placed in prolonged contact with the living tissue of the eye and eyelid, said method comprising contacting for a suitable period of time said polymer with a solution containing hydrogen sulfide or a salt thereof. 
     
     
       2. A method for reducing the irritant effect resulting when a hydrogel polymer in the shape of a contact lens and formed by the copolymerization of a major amount of a monoester of an olefinic acid selected from the group of acrylic and methacrylic acids having a single olefinic double bond and a polyhydric lower alcohol, and a minor amount of a polymerizable diester which contains at least two olefinic double bonds, is placed in prolonged contact with the living tissue of the eye and eyelid, said method comprising contacting for a suitable period of time said polymer with a solution containing a sulfonate salt of the formula ##STR11## wherein r is an integer selected from zero to five, M +  is a cation, and Q is hydrogen or M + . 
     
     
       3. The method of claim 2 in which said sulfonate salt is sodium thiosulfate. 
     
     
       4. The method of the claims of 1 and 2 wherein said solution includes a solvent medium selected from the group consisting of water, sodium borate, methanol, ethanol, propanol, and mixtures thereof and said hydrogen sulfide, or a salt thereof, or said sulfonate salt is present in a concentration of between 1% by weight and saturation in said solvent medium.